/**
 * 生成随机字符串
 */
export const randomstr = (n: number) => {
    const str = "abcdefghijklmnopqrstuvwxyzQWERTYUIOPASDFGHJKLZXCVBNM1234567890";
    let tmp = "";
    let i = 0;
    const l = str.length;
    for (i = 0; i < n; i++) {
      tmp += str.charAt(Math.floor(Math.random() * l));
    }
    return tmp;
  };